Influence of Oil on Filament Wound Composite Material Used in Automotive Gearbox

Abstract

Considering a possible use of carbon fiber reinforced polymers (CFRP) in automotive gearboxes, this paper investigates influence of oil on mechanical properties of CFRP. This particular research was a part of wide-focused project whose goal was to design a gearbox using large proportion of CFRP in order to reduce mass and noise. Part of this design was a filament wound shaft. In order to investigate an influence of oil on such part, 18 test specimens were manufactured. The specimens were simple tubes 15 x 9.9 x 300 mm with layup similar to the designed shaft. One half of the specimens was tested immediately and the other one after immersing in gearbox oil at elevated temperature of 80 °C for 83 days. Both test groups were then compared. The specimens were tested statically and dynamically in 4-point bending setup. Immersed specimens were regularly weighted, and mass progress was watched expecting diffusion behavior. The results have shown likely no negative effect of oil on CFRP and no oil diffusion in the material. Both flexural stiffness and maximal force increased and degradation of stiffness during cyclical loading decreased after oil exposure.